Apparatus for irradiating materials



Jan, 25, 1944. R. H. BARNES ,APPARATUS FOR IRRADIATING MATERIALSUriginal Filed July 1'7,l 1939 .VE E,

INVENTOR.

ATTORNEY.

PatentedJmzs, 1944 APPARATUS FOR IRRADIATING MATERIALS Richard H.Barnes, Minneapolis, Minn.

Original application July 17, 1939, Serial 284,850. Divided and thisapplication October 24, 1939, Serial No. 300,988

1 Claim.

This invention relates toa method and an apparatus for synthesis ofvitamin D. This application is a divisioni', oiv application Serial No.284,850 filed July 171939.

One object of the invention is to provide a method by means of whichvitamin D may be produced of high potency free from deleteriousmaterials. Another object is to provide an apparatus in which provitaminmaterials may be exposed to ultraviolet light rays. Other objects willbe apparent from the following description .and therdrawing, in whichFig. 1 is an elevation, partly in section-showing one form of apparatusof my invention; Fig. 2 is a sectional View taken on the line 2--2 ofFig. l; Fig. 3 is an elevation, partly in section, showing another formof irradiating apparatus of my invention.

Referring particularly to Figs. l and 2, an irradiating chamber I .ismounted vertically upon a supporting ybackboardv II by means of clampsI2. An ultraviolet generator I3, of the type known commercially as coldquartz and consisting of a closed tube of clear quartz or other materialtransparent to ultraviolet radiations 'with electrodes I4 in the twoends and containing a little mercury and a mixture of rare atmosphericgases at low pressure, is placed within the irradiating tube or chamber,and preferably sealed thereto at its ends. The electrodes I4 arecemented or sealed through the ends of Y the tube so that electricalconnections may be made at the terminals I5 to suitable sources ofelectrical energy. Side tubes I6 and II permit the entrance and exit ofthe fluid to be subjected to the ultraviolet radiation of the generatorI3.

The upper side tubeIE is connected to a delivery tube I9. having a valve20 which may be used to controll the rate of discharge of treated duid,and hence its rate ofow in the irradiating chamber lIl) and its time ofexposure to the ultraviolet radiations from the generator I3. The fluidto be treated is delivered by the tube or pipe 2I to the l er side arm II of the chamber I0. A cooling` ansrfor the entering fluid isrepresented as` A .coil around the tube 2l near theirradiatingapparatus, a cooling medium such as cold water o'i'refrigerant being circulated therethrough. Other means for cooling theincoming liquid may be employed, it being necessary to cool the liquidsufficiently so that the heat absorbed bythe liquid in its passage overthe ultraviolet light generator will not raise it labove its boilingtemperature, or above the temperature where the material isdeleteriously eiected. The

chamber itself may be cooled by coils or jacket.

In the modification shown in Fig. 3, a concentric tube 24 .is interposedbetween the ultraviolet light generator and the irradiating chamber,this tube 24 being transparent quartz or other material transparent toultraviolet light. r)The tube 24 is preterably made integral with lorsealed to the louter tube which constitutes the outer wall of theirradiating chamber I0, andthe ultarviolet generator tube I3 isconveniently centered within `this tube 24 by apertured stoppers 26 ateither end. Tubes 2'I and 28, also held in holes in the Stoppers,provide entrance and exit means for an interposed gas or liquid coolingor screening agent in the space between the irradiating chamber I0 andthe ultraviolet light generator. The liquid to be irradiated iscirculated in the annular irradiating chamber lil, by means or anentrance-side tube I'I and an exit side tube I6, which may be connectedas above described under Fig. 1. By provision of the interposed annularvspace between the generator tube and the irradiating chamber,ultraviolet light of any selected wave lengths may be screened out andabsorbed and hence cannot act upon the liquid to be irradiated in theouter chamber I0, or a cool ing fluid may be circulated to take away theheat generated by the generator.

My method of producing vitamin D by irradiation of provitamin materialin solution may be illustrated by reference to the apparatus describedand shown, although obviously other apparatus or modifications of thisapparatus may be employed or 1an enclosed ultraviolet light generatorgiving out selected wave lengths may be immersed in the dissolvedprovitamin liquid, in accordance with my method.

Referring, then, for illustration, to the apparatus shown in Fig. l, Ihave treated a solution of about 1 part of ergosterol in 100 parts ethylether by subjecting it to the ultraviolet light from a cold quartzgenerator, by passing it through the feed pipe 2|, through theprecooling coil 22, through the lower side-tube II, into the irradiatingchamber I0, where it came into direct contact with the wall of the coldquartz generator tube, and flowed out through the upper side tube I6,and was collected. By using gravity feeding of the incoming liquid froma reservoir located slightly above the elevation of the treatingchamber, the rate of flow could be readily regulated by means of thevalve 20 in the exit tube. It is important in starting the operation,that all of the air be removed from the irradiating chamber, for if thisair remains, oxygen culation in any particular apparatus, but also" uponthe amount of ultraviolet light energy of suitable Wavelength which isabsorbed by the provitamin. In one case, using the one-percentYergosterol solution in ethyl ether, 75 Cubic centimeters of liquid perminute was passed through the treating chamber. After the treatedmaterial was collected and the ether removed in a neutral atmosphere andWith'little heating, the resulting residue had a vitamin D activitybetween 400,000 and 600,000 U. S. P. units per gram of material. Inanother case, using the same apparatus, (having a chamber about 20inches long and inch in diameter and a cold quartz tube 1A; inch indiameter within it) but doubling the time of exposure to the ultravioletlight, a concentration between 800,000 and 1,000,000 U. S. P. units ofvitamin D per gram resulted.

Instead of passing the provitamin solution in direct Contact with a coldquartz ultraviolet light generator, and thereby subjecting it to all ofthe ultraviolet light generated, as well as to some heat from thegenerator, I may subject the solution to only a selected part of thegenerated ultraviolet light by providing a screening and cooling jacketaround the generator, and passing the provitamin liquid in directcontact with the jacket. This is illustrated by referring to theapparatus shown in Fig. 3 of the drawing. The space between thegenerator tube and the inner Wall of the irradiating chamber may befilled With dead air or gas or liquid, or the fluid may be circulated.

When air is used, the short penetrating wave lengths of ultravioletlight acts upon the oxygen to produce ozone, and this ozone then absorbsthe ozone-producing wavelengths of ultraviolet light so that theprovitamin solution in the outer chamber is subjected only to light freefrom ozone-producing wavelengths of ultraviolet light. This prevents anyformation of peroxides or ozone or oxygen compounds -within-the vitaminD solution and greatly improves the quality of the product, and permitslonger treatment, and hence greater concentration of vitamin D. Thecooling effect of the interposed layer of uid, especially if it is incirculation, .also prevents overheating and volatilization of theprovitamin `and vitamin solutions.

Other solvents which will dissolve provitamin materials of the nature ofergosterol, may be used such as ethyl alcohol, acetone, methyl alcohol,etc., and oils. Natural materials containing provitamin such asvegetable and animal oils may Y be circulated in direct' orindirctcontact' with the ultraviolet generator as described.

While I have shown and described the apparatus of my invention, "anddescribed illustrative examples of my methodof irradiation of provitaminmaterials bypassing them :insolution in direct contact with ultravioletlight genera'- tors of the cold quartz type, as originally generated orafter removing vundesired"vvfavelengths, I do not wish to be limitedthereby, but` restrict my invention only insofar as required `bytheprior art and the spirit of the appended claim.

Iclaim: v f 'v The method of selecting desired ultra-violet light raysgenerated from a cool quartz-encased ultra-violet light generatorcomprising passingA a current of air in contact with said generator, andremoving said air a` t a rate suicient to provide only the requiredamount of oxygen to absorb at least a portion of the ozone-producingraysfrom said generator. l RICHARDH, BARNES.

